Other than that, the scan engine will find anything you can define on your own. The problem with "simple" patterns like double tops and H&S reversals is, as easy as they are to spot by eye, they are very difficult to define specifically. The patterns vary widely in their dimensions - for instance, the "tops" of a double top can be two weeks apart, two months apart or two years apart. Also, the tops will not occur at exactly same prices, so you have to decide how close the prices have to be to be a double top, etc. That's not to say it can't be done. It's just a lot of trial and error work to get there.

The scan engine is best suited to finding combinations of indicator values, or ranges of values, or events like MACD crossovers or MA crossovers, or volume above or below average, or RSI above 80, or Slow Stoch %K below 20, etc.